As shown in FIG. 4, a door opening 1 in a back surface of a body of a vehicle such as a wagon type vehicle, SUV, etc. is opened and closed with a hatchback-type back door 2. In one example of the conventional hatchback-type back door 2, the back door 2 is automatically opened and closed with a drive device D, which is called “power back door” (See Patent documents 1 and 2, for example).
In the power back door of this type, the drive device D provided on an interior side of a rear pillar P along a door opening is connected to the back door 2 via a drive arm 3 and a rod 4. The drive arm 3 is provided in the drive device D to turn upwardly and downwardly, and the rod 4 is connected to an end of the drive arm 3 and extends upwardly. By moving the rod 4 upwardly and downwardly with the turning of the drive arm 3 about a turning shaft 30, the back door 2 is opened and closed. Patent documents 1 and 2 also disclose a control device adapted to prevent a door from colliding with obstacles upon the driving of the door with the drive device.
FIGS. 5 and 6 illustrate a typical example of a conventional structure of a connection section S between the drive arm 3 and the rod 4 of the power back door along with an area surrounding the same. Generally, in the connection section S, a spherical shaft projects from an end of the drive arm 3 and is tiltably fitted in a hemisphere-shaped bearing provided in the rod 4. And the drive device D and the drive arm 3 are covered with a pillar garnish 5 composed of a synthetic resin plate, similarly to an interior surface of a rear pillar P.
The pillar garnish 5 is cut along a rear end edge 52 to define an opening 50 along with a rear end edge of the rear pillar P. The opening 50 opens rearwardly with a vertically long configuration, and allows the entrance and exit of the connection section S between the drive arm 3 and the rod 4 (in the directions shown by arrows Y in FIG. 6). A cover member 9 is provided to close the opening 50 while allowing the turning of the connection section S. The cover member 9 is composed of a rubber plate or a synthetic resin plate exhibiting a rubber-like elasticity. An outer peripheral part 90 thereof is bonded to a peripheral edge of the pillar garnish 5, and a lip part 91 thereof contacts the rear end edge of the rear pillar P
When the back door 2 is closed, the drive arm 3 is accommodated in the vehicle compartment with the end thereof directed downwardly. When the back door 2 is opened, the drive arm 3 turns upwardly, and the connection section S between the end of the drive arm 3 and the rod 4 passes the vicinity of a lower end of the opening 50, and projects rearwardly and outwardly of the vehicle body. And the connection section S pushes the lip part 91 of the cover member 9 and enlarges a slit 93 formed in a lower end of the lip part 91 to be separated from the outer peripheral part 90 of the cover member 9. When the back door 2 is fully opened, the drive arm 3 reaches the vicinity of an upper end of the opening 50, and the connection section S projects outwardly of the vehicle body via a cut part 92 provided in an upper half of the cover member 9.
Patent Document 1: Japanese patent application laid-open No. 2003-336448
Patent Document 2: Japanese patent application laid-open No. 2004-230993